Bushing protective hood and connector



NOV. 8, 1966 w, MUSCHONG 3,284,563

BUSHING PROTECTIVE HOOD AND CONNECTOR Filed Oct. 22, 1965 United StatesPatent BUSHING PROTECTIVE HOOD AND CONNECTOR Peter W. Muschong, St.Louis, Mo., assignor to Central Transformer Corporation, Pine Bluff,Ark, a corporation of Arkansas Filed Oct. 22, 1965, Ser. No. 502,025 7Claims. (Cl. 174145) This invention relates to a device for protecting ahigh voltage terminal of a transformer and for connecting the bared endof a conductor to a transformer bushing.

Among the several objects of the invention may be noted the provision ofa protective hood and connector for transformers which minimizesexposure of electrically live parts; the provision of a hood andconnector for terminals of transformers which is enclosed except for asingle opening for a conductor and a single opening for a gap electrode;the provision of a hood and connector having only two openings for aconductor and electrode which is capable of receiving a conductor fromtwo positions 180 apart without changing the mounting of the connectoron a transformer cover bushing; the provision of a hood and connectordevice for mounting on cover bushings of transformers which is capableof locating the spark gap electrode at two positions 180 apart withoutchanging the mounting of the device on the cover bushing or requiring achange in its connection to a conductor; the provision of a hood andconnector for transformer bushings wherein maximum spacing of theconductors may be obtained; and the provision of a protective hood andconnector device having a cover which cannot be accidentally removed.Other objects and features will be in part apparent and in part pointedout hereinafter.

The invention accordingly comprises the constructions hereinafterdescribed, the scope of the invention being indicated in the followingclaims.

In the accompanying drawings, in which one of various possibleembodiments of the invention is illustrated,

FIG. 1 is a plan view of a transformer illustrating two of theprotective hoods and connectors of the present invention;

FIG. 2 is an enlarged plan view of a protective hood and connector ofthis invention with the cap removed;

FIG. 3 is a vertical section showing the connector mounted on a coverbushing of a transformer; and

FIG. 4 is a section of the-hood and connector per se taken along line 44of FIG. 3.

Corresponding reference characters indicate corresponding partsthroughout the several views of the drawings.

Referring now to FIG. 1 of the drawings, two protective hoods andconnectors 1 of the invention are shown mounted in spaced relation onthe cover of a'conventional distribution transformer 3. High voltage orprimary insulated conductors 5 for transformer 3 are received by thehood and connectors 1, a bared end of each of the conductors beingelectrically and mechanically connected to respective cover bushings 7(FIG. 3) of transformer 3. Shown mounted on the side walls oftransformer 3 are two lightning arestors 9 each of which has anelectrode 11 projecting toward the connectors 1. There is a small gapbetween the electrodes 11 and the connectors 1.

Referring now to FIGS. 2-4, the connectors 1 generally comprise aconnector body 13 which includes a metallic base 15 adapted to beattached to cover bushing 7 and an elongate upwardly projecting stemportion 17 which receives the bared end of conductor 5. Conductor 5 issecured to the connector body by clamp structure generally designated19. A gap electrode 21 projects from a portion of the clamp structure 19and the outer end of electrode 21 is positioned closely adjacent butspaced from the electrode 11 of the lightning arrestor 9.

A hood or casing 23 surrounds the connector body 13 and has tWoelliptical openings 25 and 27 therethrough in the same horizontal plane.Conductor 5 is passed through one of the openings and the gap electrode21 projects through the other. There is a cap 29 mounted on stem 17 andenclosing the upper end of casing 23. Cap 29 forces the upper portion ofclamp structure 19 against conductor 5 for clamping the conductor in theconnector.

More specifically, the connector base 15 comprises a circular disk 31projecting radially outwardly from the lower end of stem 17. An annularskirt 33 depends from the periphery of disk 31 and fits around the upperend of the cover bushing 7. A tapped hole 35 in connector body 13 opensto the bottom of disk 31 and receives a threaded stud 37 (FIG. 3) oncover bushing 7 for attaching the connector to the bushing.

Stem 17 projects from base 15 perpendicularly relative to the plane ofthe circular portion 31 of the base. The conductor 5 is received by ahole 39 extending through the stern transverse to the length of thestem. A lower clamping jaw 41 projecting from opposite sides of the stem17 has a generally arcuate groove 43 in its upper surface which isaxially aligned with the lower portion of hole 39 in the stem. Ifdesired, the groove 43 may taper downwardly from the center of stem 17to the outer edges of jaw 41 to facilitate passing of the conductor 5through the stem. The axis of jaw groove 43 is generally parallel to theaxis of the hole 39 in stem 17.

In addition to clamp jaw 41, the clamp structure 19 comprises a clampmember 45 which is integral with gap electrode 21. There is a .hole 47through clamp member 45 which is sufficiently large relative to stem 17to permit clamp member 45 to move freely on the outer end portion of thestem, thereby permitting it to be rotated or moved axially toward andaway from the clamp jaw 41. A clamp jaw 49 on clamp member 45 has agroove 51 along its lower surface which extends the full length of jaw49 and faces the groove 43 in jaw 41. The groove 51 is substantiallyperpendicular to the axis of hole 47. The elongate gap electrode 21projects from clamp member 45 at an angle of approximately to the lengthof groove 51 and also at approximately 90 to the axis of the hole 47 inthe clamp member. Due to this relation the electrode gap 21 is alwaysprojecting perpendicular to the axis of conductor 5 and is perpendicularto stem 17. The holes 25 and 27 in casing 23 are positioned 90 apart asshown in FIG; 2. Since clamp member 45 is freely rotatable on the outerend of stem 17, conductor 5 can be passed through either one of theholes 25, 27 and the gap electrode 21 can be positioned so that itprojects through the other hole.

Clam p member 45 'has a narrow, arcuate recess 50 extending outwardlyfrom hole 47 adapted to at least partially receive :a shoulder 52 :onstem 17. When shoulder 52 is in recess 50, the clamp member 45 is lockedagainst rotation relative to stem 17. This prevents inadvertent notationof gap electrode 21 when cap 29 is forcing jaw 49 toward jaw 41.However, clam-p member 45 can be freely rotated to move electrode 21between its two positions apart by lifting the clamp member aboveshoulder 52.

The casing 23 is generally cylindrical in shape and is preferably madeof an insulating material such as porcelain. At the lower end of casing23 there is an enlarged skirt portion designated 53 which surrounds theskirt 33 of the connector body and the upper end of the transformerbushing 7. An annular shoulder 55 between skirt 53 and the upper portionof the casing rests on the disk 31 of the connector base. The casing 23is rotatable to any position relative to the connector body. Weep holes57 above shoulder 55 communicate with similar weep holes or recesses 59beneath shoulder 55 to provide passages for water or moisture from theinside of casing 23 to the exterior of the connector.

Stem 17 above the hole 39 is threaded along two portions of its lengthas shown at '61 and 63. The threads 61 are separated from threads 63 byan unthreaded area in relief designated 65.

'Ilhere is an insert 67 molded in cap 29. A hole 69 in insert 67 istapped and the threads are interrupted along a break area designated 71.The threaded area 72 of insert 67 between the un-threaded area 71 andthe outer end of the insert is shorter than the area 65 without threadsin the stem 17. Also, unthreaded area 71 of the stem is longer than thethreaded portion 63 of the stem. This construction of the stem andinsert prevents inadvertent loss of the cap. When the cap is beingunscrewed and the threaded portion 72 leaves the threaded portion 61 ofstem 17, the cap will turn loosely on the stem without the threadsengaging. The cap can be intentionally removed from the stem by liftingupwardly on the cap to engage the threads 72 with the threads 63 andthen unscrewing the cap.

The lower end of insert 67 engages the top of a doubleturn lock washer73 which surrounds stem 17 and bears against the top of clamp member 45.Thus by screwing the cap 29 toward clamp member 45, the clamp member 45is forced against conductor 5.

The cap 29 has an annular recess 75 located inwardly from annular skirt79. The upper end of casing 23 is partially received in recess 75 andthe lower end of skirt 79 surrounds the upper end of the casing. Fourprojecting ribs 81 on the upper surface of the cap facilitate rotationof the cap.

In order to mount the hood and connector of the invention onto atransformer 3, the connector body 13 is screwed onto the threaded stud37 of transformer bushing 7 it is tight. Casing 23 and clamp member 45are then positioned around the stem as shown in FIGS. 3 and 4 with oneof the holes 25, 27 aligned with the axis of the hole 39 in stem 17 andwith the other of .the holes 25, 27

' and the electrode 21 positioned so that they face the electrode 1|1.As illustrated in the drawings, the gap electrode 21 projects throughhole 27 and the hole 25 is aligned with hole 39 in stem 17. Clamp member45 is then lifted and conductor 5 is passed between clamp jaws 41, 49and through hole 39 in stem 17.

Cap 29 is then screwed down on stem 17 to force clanop jaw 49 towardclamp jaw 41 until the conductor is firmly clamped between the jaws.Since hole 47 in clamp member 45 is somewhat larger than the threadedportion 61 of the stem, the clamp member 45 is free to move verticallyor rotatably on the outer end of stem 17 without interference trom thethreaded portion of the stern. On the other hand, when shoulder 52 onstem 17 is engaged in recess 50 in clamp member 45, then the clampmember can only move vertically and misalignment of electrode 21 isprevented. The hood and connector is then mounted and will shield theconnection between the conductor 5 and bushing 7 of the transformer.

By removing the conductor 5 and then rotating casing 23 clockwise by 90(as viewed from the top), conductor 5 can be passed into the connectorfrom a direction 180 from that shown in FIGS. 2-4 and at the left inFIG. 1. The conductor would then pass through hole 27 in the casing 23and the gap electrode 21 would project through the hole 25. Thisarrangement is shown for the connector 1 at the right in FIG. 1. Theconductors 5 can enter connectors 1 at positions 180 from their FIG. 1positions simply by rotating the casing 23 of the left connector 1'by 90clockwise and rotating the other connection casing 90 counterclockwise.However, the arrangement of the connectors 1 shown in FIG. 1 ispreferred since this separates conductors 5 by a maximum distance.Horizontal issuance of conductors 5 helps obtain maximum clearancebetween the conductors.

It will thus be apparent that casing 23 can be located at any of fourpositions apart and electrode 2llocked at either of two positions apart,depending on where conductor 5 is to enter the connector and thelocation of electrode 11 relative to the connector. This permits theconnector to be used interchangeably on either the left or right coverbushings, and also permits complete versati-lity of positioning :as tocable entry and electrode location.

In some prior bushing connectors three holes 90 apart are required inthe casing in order for the conductor to be passed into the connectorfrom either of two positions 1i80 apart without changing the location ofthe gap electrode. When these connectors were installed there was alwaysone open conductor hole through which birds, squirrels etc. couldcontact the live connections of the connector. If these birds or animalswere standing on top of the transformer (which is at ground potential)then there was a short to ground which caused an outage in thetransformer. Also, previous electrodes were part of the connector body.As they were fixed relative to the body, the entire cover bushing had tobe loosened and rotated for alternate locations of the electrodes. Theseproblems are eliminated with the connector of the invention since itmore completely shields the electrically live parts and permitspositioning of the electrode independent of the connector body.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructi-ons withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:

1. A protective hood and connector for attachment to a cover bushing ofa transformer comprising a connector body adapted to be attached to thebushing, a stem on the body having a hole adapted to receive a bared endof an insulated conductor, a clamp jaw on the stem engageable with saidbared conductor end when received by the stem, a second clamp jawmovable relative to the stem toward and away from the first jaw andadapted to cooperate with the first jaw for clamping a conductortherebetween, means for moving the second jaw toward the first jaw, thesecond jaw having an elongate gap electrode projecting from it at anangle of approximately 90 to the axis of a conductor when clamped by thejaws, and a generally cylindrical casing of insulating materialpositioned around the connector body, the casing having two holeslocated approximately 90 apart, the casing being movable between firstand second positions 90 apart whereby a conductor can be passed througheither one of said holes in the casing and the gap electrode can projectthrough the other hole in the casing.

2. A hood and connector as set forth in claim 1 wherein the moving meansfor the second jaw comprises a cap threaded on the stem and movabletoward and away from the second clamp member.

3. A hood and connector as set forth in claim 1 wherein the second clampjaw is loosely positioned on the stem and rotatable relative to the stembetween two positions 180 apart.

4. A protective hood and connector for attachment to a cover bushing ofa transformer comprising a connector body having a base adapted to beattached to the cover bushing, an elongate stem projecting from thebase, a hole through the stem transverse to its length adapted toreceive a bared end of an insulated conductor, a first clamp jawprojecting from the stem at opposite sides of the hole in the stem, thejaw having an elongate groove in its upper surface parallel to the axisof the hole in the stcm,a clamp member loosely slideable on the outerend of said stem and :being movable toward and away from the first clampjaw, the clamp member having an elongate second clamp jaw with anelongate groove in its lower surface for receiving said bared conductorend portion, the second jaw cooperating with the first jaw for clampinga conductor therebetween, the clamp member having an elongate gapelectrode projecting from it at an angle at approximately 90 to thelength of the groove in the second jaw, a generally cylindrical casingof insulating material positioned around the connector body, the casinghaving two holes through it located approximately 90 apart insubstantially the same plane whereby a conductor can be passed throughone of the holes into the casing and the gap electrode can projectthrough the other hole in the casing, the casing being free of otherholes through which a conductor or the gap electrode can pass, a cap forclosing one end of the casing, said cap being threadably secured on theouter end portion of the stem to move the second jaw on'said clampmember toward said first jaw for clamping the bared end of a conductorbetween the jaws.

5. A protective hood and connector as set forth in claim 4 wherein thecasing is rotatable relative to the stern and positionable at twopositions apart.

6. A protective hood and connector as set forth in claim 4 wherein theclamp member is rotatable relative to the stem between two positionsapart.

7. A protective hood and connector as set forth in claim 4 wherein boththe stem and the cap have breaks in the threads elfecting theirconnection whereby inadvertent removal of the cap is avoided.

References Cited by the Examiner UNITED STATES PATENTS 2,664,457 12/1953 Joublanc. 2,883,640 4/1959 Duenke 174-145 X 2,934,593 4/ 1960Kollinger 174-445 3,021,502 2/ 1962 Lehman.

LARAMIE E. ASKIN, Primary Examiner.

1. A PROTECTIVE HOOD AND CONNECTOR FOR ATTACHMENT TO A COVER BUSHING OFA TRANSFORMER COMPRISING A CONNECTOR BODY ADAPTED TO BE ATTACHED TO THEBUSHING, A STEM ON THE BODY HAVING A HOLE ADAPTED TO RECEIVE A BARED ENDOF AN INSULATED CONDUCTOR, A CLAMP JAW ON THE STEM ENGAGEABLE WITH SAIDBARED CONDUCTOR END WHEN RECEIVED BY THE STEM, A SECOND CLAMP JAWMOVABLE RELATIVE TO THE STEM TOWARD AND AWAY FROM THE FIRST JAW ANDADAPTED TO COOPERATE WITH THE FIRST JAW FOR CLAMPING A CONDUCTORTHEREBETWEEN, MEANS FOR MOVING THE SECOND JAW TOWARD THE FIRST JAW, THESECOND JAW HAVING AN ELONGATE GAP ELECTRODE PROJECTING FROM IT AT ANANGLE OF APPROXIMATELY 90* TO THE AXIS OF A CONDUCTOR WHEN CLAMPED BYTHE JAWS, AND A GENERALLY CYLINDRICAL CASING OF INSULATING MATERIALPOSITIONED AROUND THE CONNECTOR BODY, THE CASING HAVING TWO HOLESLOCATED APPROXIMATELY 90* APART, THE CASING BEING MOVABLE BETWEEN FIRSTAND SECOND POSITIONS 90* APART WHEREBY A CONDUCTOR CAN BE PASSED THROUGHEITHER ONE OF SAID HOLES IN THE CASING AND THE GAP ELECTRODE CAN PROJECTTHROUGH THE OTHER HOLE IN THE CASING.